The present invention relates to novel polymers and their use in a variety of binder systems and, in particular, to the use of a novel thermally depolymerisable polyoxalate or polymalonate polymer as a binder for powdered glass, ceramic or metallic materials, and as a rheological control agent in paste formulations.
Thermally depolymerisable polycarbonates have been described by F. M. Houlihan, F. Bouchard, J. M. J. Frechet and G. G. Wilson in Macromolecules 1986, 19, 13-19. The materials which are described are polycarbonates containing a tertiary group next to the main chain oxygen which were prepared by using a solid-liquid phase-transfer-catalyzed polycondensation of the bis(carbonylimidazolide) of 2,5-dimethyl-2,5-hexanediol with various other diols in the presence of powdered potassium carbonate. These polycarbonates decompose cleanly upon heating to about 220.degree. C. with liberation of volatile materials, leaving no solid residue.
In EP-0463796A we have described compositions in which at least one powdered material is admixed with at least one thermally depolymerisable polycarbonate containing the repeating units ##STR1## where R.sup.5 and R.sup.6 are the same or different and each independently represents a hydrocarbon group containing from 4 to 30 carbon atoms, the said group having a tertiary carbon atom, an allylic, propargylic or benzylic group attached directly to at least one oxygen atom.